Physiological responses to intravenous diazepam as a sedative for conservative dentistry

Comparison between intranasal and intravenous midazolam sedation (with or without patient control) in a dental phobia clinic

Two new modes of sedation; patient-controlled sedation (PCS) and intranasal sedation (INS) were compared with the traditional bolus intravenous sedation (BIVS) while delivering dental care to apprehensive patients in a specialized dental fear clinic. Effective sedation was evaluated in a randomized, prospective study in 42 ASA 1 and 2 patients, in a factorial design. Eighteen patients were sedated with .5% midazolam INS. Ten patients received intravenous PCS via a patient-controlled analgesia pump containing midazolam, and 14 patients received intermittent intravenous boluses of 1 mg midazolam given as needed (BIVS). Appropriate local anesthetic nerve blocks with 2% lidocaine with 1:100,000 epinephrine, and supplementary inhalation of nitrous oxide and oxygen via a nasal mask, were also given to all patients in the study. The dosage requirement with PCS was higher than that found with INS or BIVS. However, PCS produced some anxiety reduction when compared with INS and BIVS. It also reduced interfering movements during treatment more effectively than the other sedation modes. No complications were detected in any of the patients and they were able to leave the clinic within 1 hour after completion of treatment.

Ventilatory response to single, high dose estazolam in healthy humans

The purpose of this study was to determine the effect of oral estazolam at two and three times the usually recommended dosage (2 mg) on ventilation and respiratory drive during wakefulness. Sixty healthy subjects were randomized to receive a single oral dose of either: 1) estazolam 4 mg; 2) estazolam 6 mg; 3) placebo; or 4) morphine 0.15 mg/kg. Predrug and postdrug measurements were obtained for ventilation, respiratory cycle timing, metabolic rate, temperature, and ventilatory and mouth occlusion pressure (P0.1) responses to exogenous CO2. No difference between placebo and the study drugs was noted during eupneic breathing. During administration of exogenous CO2, morphine caused a decrease in the slope of the ventilatory (-0.4 +/- 0.1 L/min/mm Hg, P = .008) and P0.1 (-0.22 +/- 0.06 cm H2O/mm Hg, P = .015) responses. Estazolam (4 and 6 mg) had no effect on the ventilatory response to exogenous CO2. However, estazolam (6 mg) caused the P0.1 at a PCO2 of 57 mm Hg to decrease (-0.67 +/- 0.30 cm H2O, P = .005). The preservation of ventilation with the highest dose of estazolam, despite the decrease in P0.1, indicates that a compensatory strategy independent of respiratory center drive may have been activated. Sedation was a common side effect of estazolam reported in 13% and 53% of subjects at the 4 mg and 6 mg doses, respectively. We conclude that a single, high dose of estazolam does not cause ventilatory depression during wakefulness in healthy subjects.

Comparison of sublingual lorazepam with intramuscular diazepam as sedatives during oral surgery

Sublingual lorazepam (2 to 3 mg) was compared with intramuscular diazepam (0.25 mg/kg) and placebo for sedation during oral surgery under local anesthesia. Sixty patients were randomly allocated into three groups in this double-blind, parallel study. The results from this trial show that sublingually administered lorazepam provided good sedation and anxiolysis. More side-effects, such as giddiness, dizziness, and ptosis, as well as profound and prolonged psychomotor impairment, were, however, found in the lorazepam group than in those patients who had received intramuscular diazepam (0.25 mg/kg) or placebo.

Intravenous midazolam in oral surgery

Intravenously administered midazolam (0.1 mg/kg) was compared with placebo in a randomized study in 50 patients undergoing oral surgical procedures under local anaesthesia. The results obtained from this study showed that midazolam when compared to placebo had slight cardiovascular and respiratory depressant effects, diminished anxiety and caused amnesia. It also provided better operating conditions and possibly stimulated appetite.

A study of intravenous sedation with diazepam and midazolam for dentistry in Hong Kong Chinese

Fifty Hong Kong Chinese patients between 20-40 years, of ASA Gd I, undergoing third molar extraction were randomly allocated into two groups. For conscious sedation, to supplement local anaesthesia, one group received intravenous diazepam and the other intravenous midazolam. The majority in the study had never heard of intravenous sedation being available to supplement local anaesthesia during dental surgery and when given the chance to experience this method the majority found it highly acceptable. None preferred general anaesthesia for dental surgery. In this study midazolam had more advantages to the patient than diazepam; quicker onset of sedation, less pain during injection, profound anterograde amnesia and fewer postoperative complications being the main features. However, both drugs produced good operating conditions. Incidence of thrombophlebitis was low with both drugs, and may be so in Chinese compared with non-Chinese.

Aspiration pneumonitis: predisposing conditions and prevention

Aspiration pneumonitis is a common complication of general anesthesia. The lower the pH of gastric fluid and/or the larger the volume, the greater is the potential danger. In spite of preoperative fasting, an alarmingly high percentage of patients who undergo surgery may be at risk. This review discusses conditions that predispose to aspiration pneumonitis and examines current strategies for its prevention.

Venous complications of intravenous diazepam

In an attempt to clarify the confusion about venous complications from intravenous diazepam, a study of 2,468 consecutive oral surgery and general dentistry cases in which diazepam was used was undertaken. It was found that 7.9% of the patients experienced local phlebitis and 4.5%, thrombophlebitis during the week after the injection. These findings were correlated with age, weight, sexual gender, dosage, type and duration of procedure, and degree of apprehension experienced by the patient.

The effect of 50% nitrous oxide in oxygen on lower oesophageal sphincter tone

The effect of 50% nitrous oxide on the lower oesophageal sphincter was studied in eight healthy volunteers. No effect on the sphincter tone was noted in these subjects. The importance of this finding is discussed in relation to the depressant effects of nitrous oxide and other anaesthetic or sedative drugs on the reflex protective mechanisms safeguarding the respiratory tract and lungs from aspiration of acid gastric content and other foreign matter.

Intravenous benzodiazepines as anaesthetic agents: pharmacokinetics and clinical consequences

Despite extensive and numerous pharmacokinetic studies on benzodiazepines, the published pharmacokinetic data do not adequately explain the clinical differences found between different benzodiazepine derivatives after intravenous administration. Especially, correlations between initial drug responses and distributional changes of the benzodiazepines are limited. However, during the elimination phase some relationships exist between the kinetic and dynamic phenomena. Age, sex, diseases and concomitantly given drugs cause clinically important alterations in the pharmacokinetics of benzodiazepines. Generally these anxiolytics and sedatives should be considered as adjuvants to general anaesthesia, but not primarily as routine induction agents. The major reasons for this limitation are a high variability in drug response, a relatively slow onset of action and long-lasting residual effects. However, benzodiazepines have many important advantages (see Table 5) when used as intravenous inducing agents of general anaesthesia.

Poloxamer 188 as vehicle for injectable diazepam

The significant occurrence of thrombophlebitis in patients administered diazepam intravenously was described recently. This side effect has been attributed to the crystallization of diazepam and its subsequent precipitation upon contact with blood or intravenous fluids. The current study was designed to reveal whether the solubilizing capability of poloxamer 188 reduces the incidence of thrombotic and inflammatory effects of diazepam in rabbits. The incidence of early (3-hr) ear vein necrosis was 72% in the diazepam-treated ears, while the incidence of necrosis in the ears that received poloxamer 188 as a vehicle for diazepam was 25%. The occurrence of thrombosis and loss of vessel integrity also was higher in diazepam-treated ears than in those treated with diazepam plus poloxamer 188. Solubilization of diazepam with poloxamer 188 may decrease the incidence of the tested side effects.

Ventilatory pattern following diazepam and lorazepam

The effect of intravenous diazepam (10 mg) or lorazepam (2 mg) on the ventilatory pattern has been studied in two groups of ten patients prior to elective surgery. Injection of lorazepam was followed by a periodic pattern of ventilation in nine patients.

Plasma-diazepam in infants after rectal administration in solution and by suppository

Twenty infants aged 1-2 years who had previously had one attack of febrile convulsions were randomly given a single dose of diazepam rectally, either as a solution (0.7 mg/kg) or by suppository (5 mg). Plasma-diazepam levels were determined repeatedly during the first hour using gas chromatography. Rectal administration of diazepam in solution resulted in anticonvulsant plasma values within 4 +/- 1 min. Similar plasma levels were obtained only after 20-30 min in the group treated with suppositories. Diazepam in solution given rectally may therefore be useful in the acute treatment of febrile convulsions, while treatment by suppository would seem to be of little value in this respect. Moreover, diazepam in solution given rectally seems suitable for use at home in case of recurrent febrile convulsions. This treatment, however, cannot be recommended until the anticonvulsant effect and side-effects have been elucidated further.

Diazepam and flunitrazepam as induction agents for cardiac surgical operations

Diazepam and flunitrazepam were compared in equipotent doses as induction agents for premedicated patients having cardiac surgery. Both drugs caused a significant fall in arterial blood pressure, a rise in Paco2 and a fall in Pao2. There was no significant difference between the two drugs in onset time of anaesthesia, cardiovascular or respiratory depression, or quality of induction. There was also no significant difference from induction with thiopentone in these respects. Diazepam, over a 0.2 to 0.6 mg/kg range of doses showed no difference in toxicity, although induction was clinically smoother with the higher dose.

The efficacy of the laryngeal reflex in conscious sedation

The Jorgensen technique and nitrous oxide-oxygen sedation were evaluated for the risk of aspiration. Volunteers and patients were studied in the supine, semisupine, and Trendelenburg positions. Aspiration occurred in a single patient under the Jorgensen technique and could be related to the presence of a narcotic in the mixture. The incidence of tracheal soiling was lower than that with other intravenous techniques and could be attributed to the use of the semisupine position or the baseline concept of narcotic dosage in the Jorgensen technique. In the nitrous oxide-oxygen sedation technique, aspiration was not noted. The study suggests that use of a narcotic in an intravenous sedative technique increases the hazard of aspiration.

Intravenous sedation and regional analgesia

A double-blind study of 229 patients with the use of intravenous diazepam as compared with a placebo to produce sedation during local analgesia showed that significantly improved sedation occurred when diazepam was used. The diazepam was dissolved in cremophor and this reduced the pain of intravenous injection of the diazepam. One patient who received Cremophor only, showed a moderately severe allergic reaction. It is suggested that a small test dose should always be given before giving any drug which is dissolved in Cremophor.

Analysis of cardiac chronotropic responses to diazepam and bromazepam in conscious trained dogs

In conscious trained dogs, administration of bromazepam (0.3 mg/kg p.o.) or diazepam (0.3 and 1.0 mg/kg p.o.) had no influence on heart rate. A higher dose (10 mg/kg p.o.) of two benzodiazepines elicited a positive chronotropic effect which was rapid in onset and of long duration. The beta-adrenoceptor blocking agent practolol (2.5 mg/kg i.v.) did not revert heart rate after the benzodiazepines to the same level as in controls, indicating that the tachycardia was not produced by an increase in sympathetic outflow to the heart. For diazepam, a sympathetic--parasympathetic interaction cannot be excluded. However, diazepam and bromazepam significantly reduced the tachycardia which is normally observed after administration of methylatropine (0.5 mg/kg i.v.) alone or in combination with practolol. In anaesthetized dogs, bromazepam failed to modify the heart rate responses to electrical stimulation of cardiac vagal or sympathetic nerves, excluding an action on this compound on ganglionic transmission and cardiac cholinoceptors and adrenoceptors. It is concluded that high doses of diazepam and bromazepam influence the heart rate of conscious dogs in a biphasic way. Firstly, they cause a central reduction of vagal tone to the heart resulting in tachycardia. Secondly, the two drugs decrease the cardiac pacemaker rate directly. Since the overall effect is tachycardia, the central action is more pronounced.

Minor anesthesia

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Clinical and electroencephalographic assessment of diazepam in liver disease

The effects of 5 mg of diazepam intravenously were assessed in 23 patients with liver disease, 10 of whom had clinical evidence either in the past or at the time of study of hepatic encephalopathy. Transient drowsiness occurred in all patients, but prolonged deterioration in conscious level was not observed. Serial electroencephalographic recordings showed the development of activity at faster frequencies, similar to that found in normal subjects, a change which is different from that usually observed in cirrhotic patients after administration of chlorpromazine and morphine when slow-wave activity is increased.

Depression of laryngeal reflexes during keatmine anaesthesia

The competence of the laryngeal-closure reflex was assessed in a group of patients having ketamine anaesthesia and found to be depressed. All patients in a control group of conscious volunteers had a competent reflex. The possible dangers of ketamine anaesthesia without endotracheal intubation are discussed.